Convertible drilling tool



March 17, 1936. J. c. WRIGHT 2 3 CONVERTIBLE DRILLING TOOL Filed Dec. 5, 1954 Fm. F222 25 37 l as 37 As .36

I 9 27 I INVENTOQ Jrssz C. Was/17" Patented Mar. 17, 1936 AT i.

CONVERTIBLE DRILLING TOOL Jesse C. Wright, Los Angeles, Calif.

Application December 5, 1934, Serial No. 756,053

4 Claims.

This invention relates to a drilling tool and relates more particularly to a drill for use in the rotary method of well drilling. A general object of the invention is to provide a simple, practicaland improved convertible well drill.

In the drilling of oil and gas wells with the rotary method it is often advantageous to drill a pilot bore of relatively small diameter and then enlarge the pilot bore to the required size. Rapid progress and a straight hole or bore may be obtained by using only a relatively light drilling pressure on the drill making the pilot bore. In enlarging the pilot bore a pilot bit follows the previously formed pilot bore to effectively guide the tool and a heavy drilling. or feeding pressure may be put on the bore enlarging cutter without danger of deviating from the vertical. Heretofore it has been the usual practice to employ different or separate tools to drill the pilot bore and to enlarge the pilot bore.

One of the objects of this invention is to provide a well drill that may be. used to drill a pilot bore and then employed to enlarge the pilot bore.

Another object of the invention is to provide a well drill that may be readily converted from a tool for drilling a pilot bore to a tool or drill for enlarging the pilot bore.

Another object of the invention is to provide a well drill that comprises a shank having a bit at its lower end adapted to make a pilot bore, and a guide on the shank above the bit for guiding the bit during the drilling of the pilot bore and that may be replaced by a cutter for enlarging the pilot bore.

' A further object of the invention is to provide a simple, convenient and dependable means for locking the threadedly connected parts of a well tool against disconnection.

The various objects and features of my invention may be fully understood from the following detailed description of a typical preferred form and application of my invention, throughout which description reference may be made to the accompanying drawing, in which:

Fig. 1 is a side elevation of the drill provided by this invention operating to enlarge a pilot bore illustrating one quarter of the drill in longitudinal cross section. Fig. 2 is a side elevation of the generally, a shank ID, a bit II on the lower end of the shank operable to drill a pilot bore, means l2 for locking the bit against displacement from the shank ill, a. removable guide l3 on the shank I0 and a cutter I4 adapted to replace the guide l3 to enlarge the pilot bore.

The body or shank H! of the tool is adapted to be connected to the lower end of a drilling string and is designed or constructed to carry the bit II and the guide l3 and cutter M. In practice the shank I0 may be an elongate integral member as illustrated in the drawing. A screw threaded pin [5 or its equivalent is provided on the upper end of the shank Ill to facilitate the connection of the shank ID with the drilling string. The shank l B is preferably of round cross section and has an upper portion I6 and a lower the invention a tapered screw-threaded pin 25 is provided on the lower end of the shank it to carry the bit' I i. The pin 2! is of reduced diam eter providing a downwardly facing annular shoulder 22 at its upper end. A central longitudinal fluid passage 23 extends through the shank ill to conduct the circulation fiuid down wardly to the bit II.

The cutter head orbit H is provided to drill the pilot bore B and following this operation is adapted to operate in the pilot bore B to guide the drill when the cutter I4 is enlarging the bore. The bit I l includes a body or shoe 24 threaded to the shank l0 and locked against detachment therefrom by the means l2. The shoe 24 has a central screw-threaded socket 25. in its upper end to receive the pin 2|. The upper end of the shoe 24 is preferably flat to bear upwardly against the shoulder 22. The lower end of the shoe 24 may be conical or tapered downwardly and inwardly as illustrated throughout the drawing. The socket 25 continues below the end of the pin 2| to form or provide a fluid chamber 23 at the lower end of the fluid passage 23.

Means is provided on the shoe 24 to cut or drill the pilot bore B and to later operate in the pilot bore to guide the drill when it is enlarging the bore. The cutting and guiding means is preferably in the form of a plurality of cutting blades 21 projecting from the shoe 24 at circumferentially spaced points. In the particular case illustrated in the drawing there are four equally spaced blades 21. The blades 21 project outwardly and downwardly from the shoe 24 and lie in substantially vertical radial planes. preferred construction the blades -21 are of substantial length to have long reaming and guiding edges 28. As shown in Fig. 2 of the drawing the edges 28 engage the side wall of the bore B to ream and smooth it and, as shown in Fig. l of the drawing, the edges 28 engage the wall of the bore B to guide the drill while the cutter I4 is enlarging the bore. The lower ends of the blades 21 are provided with cutting edges 29. The cutting edges 29 are curved upwardly and inwardly and the lower portions of the blades 21 are curved forwardly relative to the direction of rotation of the drill. Upwardly extending openings or notches 30 may be provided in the lower ends of the blades 21. The cutting edges 29 are adapted to act on the formation on the bottom of the pilot bore B during the forming or drilling of the pilot bore. The blades 21 extend upwardly to points adjacent the upper end of the shoe 24 and their upper ends are preferably inclined downwardly and outwardly as illustrated in Figs. 1 and 2 of the drawing. Ports 9 are provided in the lower wall of the shoe 214 to discharge the circulation fluid downwardly between the blades 21.

The means |2 for locking the bit H on the shank I is such that the bit may be tightly and fully threaded on the pin 2| and then securely and dependably locked against unthreading from the pin. In accordance with the broader aspects of the invention the means |2 may be employed to lock various threadedly connected parts of well drilling tools against disconnection, for example, the means may be used to lock sections of a sectional stem or shank against disconnection or maybe employed to lock the guide 3 or the cutter 4 against unthreading from the shank I0 of the tool illustrated in the drawing. In the particular well tool being described the means I2 is utilized to prevent disconnection of the bit I I from the shank II), it being understood that this typical use or application of the lock means I2 is not to be construed as limiting or restricting the invention.

' The lock means I 2 includes rigid or fixed parts 3| on one of the members to be locked against disconnection. In the particular case illustrated in the drawing the lock parts 3| are preferably provided on the bit I I. The parts 3| are in the nature of cars or lugs rigidly connected with the shoe 24. The lugs 3| are welded or otherwise fixed to the upper ends of the blades 21 and project upwardly beyond the upper end of the shoe 24. The inner sides of the lugs 3| are shaped to substantially conform to and bear against the upper end portion of the shoe 24. In practice the lugs 3| may be substantially rectangular in transverse cross section and. may have their upper ends bevelled or inclined downwardly and outwardly. I

The lock means |2 includes tapered or threaded sockets 32 in the shank portion |1 above the shoulder 22. A look part or screw 39 is adapted to be threaded in a socket'32 to cooperate with a lug 3| to prevent unthreading of the shoe 24 from the pin 2|. The screw 39 may be socket headed as illustrated in Fig. 4 of the drawing. It is a feature of the invention that the lugs In the 3| and sockets 32 are related so that 9. lug 3| occurs adjacent or immediately behind a socket 32 regardless of the rotative position assumed by the bit I I when threaded against the shoulder 22. Where there are four blades 21, two lugs 3| may be attached to diametrically opposite blades 21. When the lugs 3| are spaced 180 apart there are three sockets 32, spaced 120 apart as shown in Fig. 4 of the drawing. With this relating of the lugs 3| and the sockets 32 there is an exposed or accessible socket 32 adjacent or immediately in front of a vertical plane defining the front of a lug 3|. threaded on the pin 2| the screw 39 is threaded in the exposed socket 32 in front of an adjacent lug 3| to prevent unthreading of the shoe from the pin.

The guide I3 is provided to guide the tool during the drilling of the pilot bore B and in accordance with the invention the guide is removable from the shankl0 so that it may be replaced by the bore enlarging cutter M. The guide |3 includes a tubular body or sleeve 33 having an internal thread 34 for cooperating with the thread 20 on the shank l0. Before the attachment of the bit I to the shank H) the sleeve 33 may be passed upwardly over the lower end of the shank and brought to a position for threading on the shank below the shoulder 9. The upper end of the sleeve 33 is adapted to bear upwardly against the shoulder I!) to limit the threading of the sleeve on the shank and for the transmission of thrusts from the guide to the shank. The sleeve 33 may be of substantially the same diameter as the flange l8 and its lower end may be inclined or beveled. A plurality of circumferentially spaced grooves 35 is provided in the sleeve 33. The grooves 35 extend downward- 1y from the upper end of the sleeve 33 and terminate at upwardly facing shoulders 36. In accordance with the invention the side walls of the grooves 35 are channeled or undercut.

Bearing members or guide members 31 are arranged in the grooves 35 and project from the sleeve 33 to cooperate with the wall of the'pilot bore B. The members 31 are in the nature of formation engaging pads and have blunt or rounded outer surfaces for contacting. with the wall of the. bore B. It is preferred to form the guide members 21 of brass or the like so that they may be readily cut or milled away in the event that it becomes necessary to run a fishing tool down over the drill. The guide members 21 are removably locked or retained in the grooves 35. Dove-tailed tongues or flanges 38 are provided on the. opposite longitudinal sides of the members 31 to cooperate with the undercut side walls of the grooves 35. The flanges 38 cooperate with the undercut walls of the grooves to positively hold the guide members against outward displacement from the grooves. The lower ends of the guide members 31 engage or rest on the shoulders 36.

In accordance with the invention the act of threading the sleeve 33 to its position on the shank l0 locks the guide members 31 against displacement from the grooves 35. The upper'ends of the members 31 are substantially flush with the upper end of the sleeve 33--and thus engage or are immediately adjacent the shoulder l9 when the sleeve is threaded to its final position on the shank. The guide members 31 are proportioned so that their outer active surfaces are spaced approximately the same distance from the vertical center of the drill as the outer guiding edges 28 ofthe blades 21. During the drilling of the After the bit shoe 24 has been fully.

pilot bore 13 the circumierentially spaced guide members 21 are adapted to engage the formation atthe side wall of the bore some distance above the bit I I to efiectively guide the bit to drill a straight vertical bore.

The cutter I4 is provided to replace the guide [3 after the drilling of the pilot bore B and is operable to enlarge the pilot bore to the required diameter. The cutter It includes a tubular shoe or sleeve-like body 40 having an internal thread 4| for cooperating with the-thread 20 of the shank i0. Following the removal of the guide l3 from the shank the. body 40 of the cutter I4 is adapted to be passed upwardly on the shank and then threaded in position so that its upper end bears against the shoulder I9. The cutter It includes a plurality of spaced cutting parts 82. The cutting parts 42 may be in the nature of blades projecting outwardly and downwardly from the body 40. In the particular case illustrated in the drawing there may be four blades 42. The blades 52 are provided at their lower ends with cutting edges 63. The cutting edges act on the formation at the shoulder S occurring between the pilot bore B and the adjacent enlarged portion of the well W. In practice the cutting edges '43 may be straight and substantially horizontal. The cutting blades 42 are pro.- vided with outer edges M for reaming or smoothing the wall of the enlarged well W.

It is believed that the utility and practicability of the well drill of the present invention will be readily understood from the foregoing .detailed description. When it is desired to drill the pilot bore B the guide I3 is passed over the lower end of the "shank l0 and threaded on the shank to the position where the upper end of the sleeve 33 bears against the shoulder l9; Theshoe 26 of thebit II is then threaded on the pin 2|. As described above, the lugs 3| and sockets 32 are related so that a lug 3| is located adjacent and rearward of an exposed socket 32 when the shoe 24 is threaded to its final position on the pin 2| The lock screw 39 may be threaded in the said exposed socket 32 in front of the lug 3| to positively prevent unthreading of the shoe 24 from the pin. The drill may then be connected with a drilling string and run into the well in the usual manner. When the drill is rotated and fed downwardly the cutting blades 21 operate to form or drill the pilot bore B. The guide members 81 may contact the wall of the bore B above the bit to drill a straight vertical bore.

Following the drilling of the pilot bore B the drill is pulled or removed from the well and the bit I I is detached from the shank ill. The sleeve 33 of the guide I3 is then unthreaded from the shank and passed downwardly over the lower end of the shank. The body 40 of the cutter I4 is passed upwardly over the lower end of the shank l8 and threaded on the shank to have its upper end bear against the shoulder l9. The bit I I- may then besecured to the lower end of the shank and locked in place by the means l2. It is very desirable to lock the bit I I on the shank when the tool is employed to enlarge a pilot bore. The pilot bore may be oversizedat points and the lower portion of the tool and the bit may whip about at such enlarged points and this whipping action may tend to detach the bit ll train the shank. The means l2, of the invention, dependably and positively locks the bit ll against detachment from the shank when the tool is enlarging the pilot bore. The tool or drill is passed or run into the well and rotated and fed downwardly in the usual manner. The pilot bit H. enters and operates in the pilot bore B while the blades 42 are acting on the shoulder S to enlarge the bore. The edges 28 of the blades 21 engage the wall o f the bore B to effectively guide the drill. Because of this function of the pilot bit II a heavy drilling or feeding pressure may be applied to the drill during the enlarging ofthe bore without danger of the drill deviating irom the vertical. The drill .is thus very rapid and eflicient in the drilling of the well. It is to be noted that the present invention provides a well drill in which a single shank and a single pilot bit may be employed in the drilling of a pilot bore and in the enlarging of the bore.

Having described only a typical form and application of my invention, I do not wish to be limited or restricted to the specific form and. application herein set forth, but wish to reserve to myself any modifications or variations that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. In awell tool, two threadedly connected sections, one section having spaced openings, spaced projections on the section, the openings and projections being related so that an opening is adjacent a projection when the sections are fully connected, and a lock part adapted to be threaded in said opening to cooperate with said projection to prevent unthreading of the sections.

2. In a well tool, two threadedly connected sec'- tions, one section having spaced openings, circumferentially spaced cutting parts on the other section, projections on the cutting parts, the

openings and projections being related so that an opening is adjacent a projection in any relative rotative position assumed by the sections, and a lock part adapted to be arranged in said opening to cooperate with said projection to prevent unthreading of the sections.

3. A well drill including a shank having circumferentially spaced openings spaced from its lower end, a bit threaded on the lower end of the shank, circumferentially spaced lugs projecting upwardly from the bit, the openings and lugs being related so that a lug is adjacent an open- .ing regardless of the rotative position assumed by the bit relative to the shank, and a lock part adapted to be threaded into an opening to cobit.

4. A well drill including a shank having circumferentially spaced openings spaced from its lower end, a bit threaded on the lower end of the shank, circumferentially spaced cutting elements operate with a lug to prevent unthreading of the on the bit, lug's projecting upwardly from the elements, the openings and lugs being related so that a lug is adjacent an opening regardless of the rotative position assumed by the bit, and a screw adapted to be threaded into an opening to cooperate with a lug to prevent unthreading of the bit from the shank.

JESSE C. WRIGHT. 

